Method randomizeSlopeValue

src/Encoder/AffineCipher.js:204–217

* Generates a random slope setting value. * @protected * @param {Random} random Random instance * @param {Setting} setting Setting instance * @return {string} Random slope setting value

(random, setting)

   * @return {string} Random slope setting value
   */
  randomizeSlopeValue (random, setting) {
    const alphabetSetting = this.getSetting('alphabet')
    if (alphabetSetting.isValid()) {
      const alphabet = alphabetSetting.getValue()
      const m = alphabet.getLength()

      // Create range based on alphabet and filter coprime values
      // Don't use caesar cipher slope (a=1) if possible
      const range = alphabet.getCodePoints().map((_, i) => i + 1)
      const coprimes = range.filter(a => a > 1 && MathUtil.isCoprime(a, m))
      return coprimes.length > 0 ? random.nextChoice(coprimes) : 1
    }
    return null
  }

  /**
   * Generates a random intercept setting value.